Dec. 11 - Jan. 10 Was One of The Warmest 31-Day Periods On Record During December and January

Several days ago, a story was posted here about how the final 8 days of December 2011 ranked among the warmest on record across South Central Nebraska and North Central Kansas. However, this pronounced early-winter warmth continued well into January as well, prior to the invasion of a strong Arctic cold front on Jan. 11, 2012. Now that this prolonged stretch of above-normal temperatures has been interrupted...at least briefly...it's time to take a closer look at where the last month ranked historically in terms of warm winter weather (for some insight as to why the weather pattern turned so mild, please refer to this story.)

Below is a series of tables...with the first set of tables focusing SPECIFICALLY on the period between Dec. 11 - Jan. 10...

The first series of tables, reflecting data for four chosen sites within the NWS Hastings coverage area, depict where the 31-day period between Dec 11, 2011, and Jan. 10, 2012 ranked historically versus all other Dec. 11 - Jan. 10 periods on record. For each site, rankings are given for AVERAGE DAILY HIGH TEMPERATURE and also for the MEAN DAILY TEMPERATURE, which is simply a mathematical average of the daily highs and lows. For climate purposes, the MEAN DAILY TEMPERATURE is typically used to make "official" rankings, since it accounts for both the highs and lows. Here are some highlights that stand out from the first set of tables:

1.) For all four sites, both the AVERAGE MEAN TEMPERATURE and AVERAGE HIGH TEMPERATURE between Dec. 11, 2011, and Jan. 10, 2012, ranked within the Top-3 warmest on record for all Dec. 11 - Jan. 10 periods, with records dating back at least 100 years. For both Grand Island and Smith Center, both categories ranked as the outright warmest on record.

2.) For all four sites represented here, and in both temperature categories, three or four of the Top-5 warmest Dec. 11 - Jan. 10 periods on record have occurred within the last 12 years! The most recent stretch of pronounced warmth during this time frame was between Dec. 2005 and Jan. 2006. Prior to the last 12 years, a few other notable stretches of mid-December to early-January warmth included Dec. 1991 - Jan. 1992, Dec. 1986 - Jan. 1987, and Dec. 1938 - Jan. 1939

Between December 11, 2011 and January 10, 2012 (period of 31 days)...

- High temperatures at the Grand Island airport climbed to at least 50 degrees on 15 days, and reached at least 60 twice. Of these 31 days, 28 featured above-normal daily mean temperatures.
- High temperatures at the Hastings airport climbed to at least 50 degrees on 11 days, and reached at least 60 twice
- High temperatures at the Kearney airport climbed to at least 50 degrees on 14 days, and reached at least 60 three times
- High temperatures in Smith Center, KS, climbed to at least 50 degrees on 15 days, reached at least 60 four times, and hit 70 once

For the following tables, temperature records date back to the following years:

Now here is a look at the data presented in the second set of tables...

In the section above, all data focused on the SPECIFIC 31-day period from Dec. 11 - Jan. 10. However, weather and climate data and trends do not adhere to specific sets of days, and definitely don't "fit neatly" into calendar months.

Therefore, to put this recent warm stretch into a bit wider and more meaningful context, it helps to compare it to ALL 31-day stretches that have occurred during the months of December and January, which are the climatologically coldest two months of the year. In the tables below, the warmest 31-day stretches at ANY point during the months of December and January are listed for Grand Island, which has one of the longest and most reliable climatological records of any site in the NWS Hastings coverage area.

PLEASE NOTE: In the table below, multiple "overlapping" 31-day periods of warm weather during the same Dec.- Jan. period are omitted.
Here are some highlights that stand out from the table below:

1.) At Grand Island, for the 31-day stretch between Dec. 11, 2011, and Jan. 10, 2012, the average mean temperature ranked as the
FOURTH-WARMEST 31-day stretch on record within the entire months of December and January. Per the average high temperature, this recent stretch of warmth ranked NINTH-WARMEST all-time.

2.) It is readily apparent from the data below that other prolonged stretches of December and/or January warmth have occurred during fairly recent winters such as 2005-2006, 2002-2003, 1999-2000 and 1991-1992.

3.) In terms of the warmest true calendar months on record for December and Jaunary (fitting into the Dec. 1-31 and Jan. 1-31 periods), their influence is also quite evident in the table. In terms of mean daily temperature, the warmest Decembers on record in Grand Island were in 1896 (35.4 degrees) and 1918 (35.2 degrees). For January, the warmest on record were in 2006 (38.4 degrees) and 1933 (36.4 degrees). In fact, January 2006, just six years ago, was by far the warmest of all December and January calendar months on record.

Some of The Warmest
31-Day Periods on Record
Between Dec. 1-Jan. 31

(Average Mean Temperature)

GRAND ISLAND

Some of The Warmest
31-Day Periods on Record
Between Dec. 1-Jan. 31

(Average High Temperature)

GRAND ISLAND

38.6 degrees - Dec. 22, 2005 - Jan. 21, 2006

50.7 degrees - Jan. 1-31, 2006

36.4 degrees - Jan. 1-31, 1933

50.5 degrees - Jan. 1-31, 1933

36.0 degrees - Dec. 3, 1896 - Jan. 2, 1897

48.2 degrees - Dec. 20, 1922 - Jan. 19, 1923

35.7 degrees - Dec. 11, 2011 - Jan. 10, 2012

47.8 degrees - Dec. 1-31, 1957

35.3 degrees - Dec. 6, 1991 - Jan. 5, 1992

47.7 degrees - Dec. 30, 1985 - Jan. 29, 1986

35.2 degrees - Dec. 1-31, 1918

47.6 degrees - Dec. 21, 1901 - Jan. 20, 1902

35.0 degrees - Dec. 30, 1920 - Jan. 29, 1921

47.6 degrees - Dec. 9, 2002 - Jan. 8, 2003

35.0 degrees - Dec. 1-31, 1931

47.5 degrees - Dec. 23, 1999 - Jan. 22, 2000

34.5 degrees - Dec. 9, 2002 - Jan. 8, 2003

46.6 degrees - Dec. 11, 2011 - Jan. 10, 2012

This page was composed by the staff at the National Weather Service in Hastings, Nebraska.